1. Field of the Invention
The invention relates to a device for conveying a continuous shingled or overlapping sheet or copy stream to a rotary printing press, with a conveying table, at least one endless, revolvingly drivable conveyor belt surrounding the conveying table, and at least one suction box disposed underneath the conveying table and being connected through suction openings with the underside of the conveyor belt, the conveyor belt being formed with through-perforated suction holes, the suction box being formed with at least two suction chambers subjectible to negative pressure or vacuum independently of one another.
The published German Patent Document DE 42 03 511 A1 has already disclosed a device for conveying a continuous shingled sheet stream to a sheet-processing machine. One vacuum chamber is permanently subjected to vacuum from a vacuum or negative pressure source, while a further vacuum or negative pressure box in front of the front lays is convertible or changeable over from vacuum or negative pressure action to overpressure action. The further vacuum box is associated both with a vacuum or negative pressure source and also with an overpressure source, while the vacuum box is connected only to a vacuum or negative pressure source. The changeover from suction air to blast air in the further suction box is accomplished under the control of a sensor system which, coupled to a delay unit, initiates a jolt of blast air in the further suction box in front of the front lays. A disadvantage of this heretofore known device is, on the one hand, the condition that it is necessary to provide an overpressure source and, on the other hand, that a jolt or blast of air in the alignment region may result in the occurrence of inaccuracies in the feeding of the sheets.
2. Summary of the Invention
Proceeding from the aforedescribed state of the prior art, it is accordingly an object of the invention to provide a device for conveying a continuous shingled sheet stream and, more particularly, to such a device in which a suction module is realized by using extremely simple means.
With the foregoing and other objects in view, there is provided, in accordance with the invention, a device for conveying a continuous shingled or overlapping sheet or copy stream to a rotary printing press, with a conveying table, at least one endless, revolvingly drivable conveyor belt surrounding the conveying table, and at least one suction box disposed beneath the conveying table and being connected through suction openings with the underside of the conveyor belt, the conveyor belt being formed with through-perforated suction holes, the suction box being formed with at least two suction chambers subjectible to negative pressure or vacuum independently of one another, comprising a base member forming a suction box, profiled guide sections accommodated in the base member, suction ducts formed between edges of the profiled guide sections and boundaries of the base member, the edges forming a seal, and the suction ducts extending in different planes in the base member.
In accordance with another feature of the invention, the first and the second profiled guide sections are disposed above one another in the base member.
In accordance with a further feature of the invention, the sheet or copy stream is conveyable in a transport plane, the base member being connected, on a side thereof facing away from the transport plane, to a suction plate.
In accordance with an added feature of the invention, the suction plate has sealing strips.
In accordance with an additional feature of the invention, the first and the second profiled guide sections are U-shaped.
In accordance with yet another feature of the invention, the first and the second profiled guide sections have bent-away ends engaging beneath a side of the conveyor belt.
In accordance with yet a further feature of the invention, the device includes a suction plate having sealing lips, the bent-away ends of the first and the second profiled guide sections are in contact with the sealing strips of said suction plate.
In accordance with a concomitant feature of the invention, the suction ducts in the base member extend in at least two parallel planes.
By employing the profiled guide sections embedded in the base member, for the sealing of the suction ducts, it is possible for suction air to be routed in a plurality of planes in the base member. Assurance is thereby provided that an effective vacuum, which is not diminished by leaks, is in the suction chambers more remote from the suction-air source; moreover, a flat surface is formed on the underside of the base member, which permits a relatively simple assembly.
A first profiled guide section and a second profiled guide section are fixed in location in the base member. The first profiled guide section and the second profiled guide section are provided on top of one another in the base member. The base member is connected, on a side thereof facing away from a material-transport plane, to a suction plate, wherein sealing strips are embedded. The sealing strips are formed of a sealing material, such as sponge rubber, for example, which is capable of compensating for large sealing-gap tolerances. The bent metal parts can thereby be formed with economically manufacturable tolerances. Because the first profiled guide section and the second profiled guide section are U-shaped and also have bent-away end regions, it is possible, during assembly or installation of the suction plate, to achieve a sealing of the suction ducts, which are respectively bounded by the profiled guide sections.
With the suction plate installed, the bent-away end regions are pressed against the sealing strips of the suction plate in such a manner that the outer portions of the bent-away end regions constitute a boundary of the suction duct, and the inner edges engage beneath the conveyor belt. The construction of the first and second profiled guide sections makes it possible for two suction ducts, independently of one another and sealed with respect to one another, to be provided in one base member.
Other features which are considered as characteristic for the invention are set forth in the appended claims.
Although the invention is illustrated and described herein as embodied in a device for conveying a continuous shingled sheet stream, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.
The construction and method of operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings, in which: